Internet juggernaut Alibaba made history on Friday when it went public in the largest U.S. stock market debut ever, cementing China’s place as a world leader in e-commerce and promising fierce competition to Silicon Valley tech giants.

Its stock rose 38 percent Friday over the $68 per-share price set Thursday night, closing at $93.89. At that price, Alibaba is worth $231 billion, more than some of the highest-profile tech companies: Facebook, Twitter, Amazon and Oracle. It is the 12th most valuable company in the world based on market capitalization, a group led by Apple and ExxonMobil, according to research firm FactSet.

The company raised $21.8 billion on Thursday night, setting the record for the largest IPO in the United States and handily beating the previous top IPO of $19.7 billion set by Visa in 2008. It may well end up setting a world record, with another $3 billion expected from an additional 48 million shares that the New York Stock Exchange said the underwriting banks would sell.

That would give the company an estimated $25 billion, surpassing the current record-holder, Asian financial company Agricultural Bank of China. The largest tech IPO before Friday was Facebook’s; it raised $16 billion in 2012.

“This is a very unique situation,” said Reena Aggarwal, a professor of business administration and finance at Georgetown University. “This is a company that dominates 80 percent of the Chinese e-commerce market and is looking for global domination.”

Alibaba’s success is a game-changer for Silicon Valley, creating more competition in an already cutthroat tech boom. The region has acutely felt the growing presence of Alibaba, whether through its investments in valley companies Lyft and Tango, the opening of Alibaba-owned companies such as e-commerce startup 11 Main in San Mateo, or the threat it poses to eBay and Google, whose profit margins are about one-quarter of Alibaba’s. The world’s largest online commerce company, Alibaba is a collection of marketplaces for consumers and businesses, with assorted Internet services. It handles more business than eBay and Amazon combined, and on Singles Day in November, China’s equivalent of Black Friday, did $5.8 billion in sales.

Tech companies such as Lending Club that have filed IPOs but haven’t wanted to compete with Alibaba for the spotlight will likely rush to trade, hoping to ride the coattails of Alibaba’s success. But they may face more critical investors because Alibaba’s impressive finances — its sales topped $8.46 billion last year and profits reached $3.77 billion — have raised the bar for IPO-bound companies, according to some industry experts.

“The scrutiny is going to increase,” said Vineet Jain, co-founder and CEO of Mountain View software company Egnyte, which is planning an IPO in 2015. “Alibaba may have set the bar for a new level of attractiveness” to investors.

Alibaba’s most indelible mark, however, will be on Yahoo, its second-largest shareholder, which will make roughly $6 billion after taxes by selling some of the Alibaba shares it acquired for $1 billion in 2005. That money, which experts expect will be returned to shareholders and spent on acquiring startups, could be the arsenal that spells an end to many of CEO’s Marissa Mayer’s troubles and helps Yahoo catch up with online ad rivals Google and Facebook.

Alibaba shares opened at $92.70 and rose dramatically in the first minutes of trading to just shy of $100. Analysts reported 100 million shares traded within the first 10 minutes. By comparison, about 57 million Twitter shares changed hands in the first 30 minutes of trading.

Some analysts worry the high price tag could mean Alibaba is overvalued.

“This is headed in a dangerous direction,” said Brian Hamilton, chairman of finance research firm Sageworks.

But compared with Silicon Valley tech IPOs such as Twitter, which went public without a profit and amid questions about whether it could make one, Alibaba is “coming to the market later, much more mature, much more established, not a startup by any means,” said Paul Boyd, managing partner at ClearPath Capital Partners in San Francisco. “And that’s primarily why this is the biggest IPO in history.”

As its empire grows, experts expect Alibaba will make acquisitions and further embed itself in Silicon Valley.

“Alibaba is going to have so much cash it’s going to go on a spending spree and buy Silicon Valley companies,” Aggarwal said.

In an interview Friday with CNBC, Alibaba founder and CEO Jack Ma, a former English teacher, said while “the instinct of an entrepreneur is to build things yourself,” Alibaba would seek to acquire companies that are aimed at “helping small businesses.”

Yahoo, too, is expected to use its cash windfall to make some acquisitions. Yahoo Chief Financial Officer Ken Goldman has said the company will return about half the after-tax proceeds to Yahoo’s shareholders, probably through stock buybacks, but CEO Mayer will likely use some of the remaining $3 billion for deals to buy other companies, added analyst Carlos Kirjner of Bernstein Research.

After Friday’s trading debut, Yahoo still holds about 400 million shares in Alibaba, amounting to 16 percent of the Chinese company and worth at least $26 billion. All told, that means Yahoo will have gained at least $41 billion on its original $1 billion investment.

Yahoo shares sank slightly on Friday, almost 3 percent to just under $50. Some analysts said the drop was due to investors pulling out because they no longer needed Yahoo as a conduit to Alibaba. A piece of the Chinese giant was now theirs to have.

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